Pressure operated{13 positive displacement shuttle valve

ABSTRACT

A shuttle valve which requires positive pressure to provide positive displacement thereof.

United States Patent Payne 1 1 Feb. 15, 1972 [54] PRESSUREOPERATED-POSITIVE [56] References Cited DISPLACEMENT SHUTTLE VALVEUNITED STATES PATENTS v' H. Pa ,T [72] Inventor ex 2,821,972 2/1958Banker ..137/112 x Assignw Cameron Iron s .T 3,215,163 11/1965Henderson... ..25l/l86X 3,258,022 6/1966 Thompson.... ......l37/ll2 X[22] 3,370,611 2/1968 Flint ..251/175x 1211 Appl.No.: 877,120

Primary ExaminerRbert G. Nilson 251/190, 251/282 [57] ABSTRACT Int."F16k A shuttle valve requires positive pressure to provide [58] Fieldof Search ..137/ 112551117], 865251.22; 2133127852, positive disphcememth r f 5 Claims,4Drawing Figures "i ,5 /0 |-Z 1 H I i /9 /7 J/ /6 2o 195/ 7 37 a 9 1 1 1 1 1 11 "f 4i i 32 3i 34 i "=1, 7.5 m 1 50 g A 1 3 a aPRESSURE OPERATED-POSITIVE DISPLACEMENT SHUTTLE VALVE BACKGROUND Shuttlevalves are known in the art. Usually, however, shuttle valves are of thevelocity type. That is, the piston of the shuttle valve is caused toswitch from one position to another position as a direct result of arelatively large pressure supplied to the piston which pressure isproduced by a significant fluid flow (in the case of a hydraulic valve).

Shuttle valves of the velocity type have a distinct disadvantage in theapplication wherein a relatively small fluid flow is provided. Such asmall fluid flow frequently is insufficient to apply enough pressure tothe piston to move said piston from one position to another position. Inthis situation, it frequently happens that the piston is shifted to anintermediate point in the valve. Since the piston has certain amount ofclearance therearound, and since the fluid flow is relatively small, thefluid leaks around the piston and the valve does not assume either ofthe discrete positions. In this case, the effect of a shuttle valve istotally lost and the valve becomes essentially useless and, perhaps,dangerous.

SUMMARY OF THE INVENTION To avoid the problems associated with avelocity-type shuttle valve, the instant pressure operated positivedisplacement type shuttle valve is provided. In this valve, the pistonincludes ports which interconnect the inlet and outlet ports on thevalve. Consequently, little or no leakage around the piston ispermitted. Moreover, the piston is not moved until the pressure appliedby the input unit is appropriately applied thereto. Since the pistonincludes the aforesaid interconnection ports, the piston must be totallydisplaced in response to a pressure at the inlet port inasmuch as thepressure applied thereto cannot be relieved until the piston port isaligned with the outlet port of the valve.

Consequently, one object of this invention is to provide a new shuttlevalve.

Another object of this invention is to provide a shuttle valve which ispressure operated.

Another object of this invention is to provide a pressureoperatedshuttle valve which requires positive displacement of the shuttle pistonto be effective.

Another object of this invention is to provide a shuttle valve which ishydraulically balanced.

Another object of this invention is to provide a pressureoperatedpositive displacement shuttle valve which is utilized in an underwatercontrol system.

DESCRIPTION OF THE DRAWINGS FIG. I is a cross-sectional view of theinstant shuttle valve shown in a schematic system configuration.

FIG. 2 is a cross-sectional view of the shuttle valve taken along thelines 2-2 in FIG. 1.

FIG. 3 is a cross-sectional view of the instant valve taken along thelines 3-3 in FIG. 1.

FIG. 4 is a cross-sectional. enlarged view of the fluid seal utilized inthe instant valve.

DESCRIPTION OF THE PREFERRED EMBODIMENT This description refers to thedrawings noted supra in which drawings similar components bear similarreference numerals.

Referring now to FIG. 1, there is shown a cross-sectional side view ofshuttle valve 10. The valve is schematically represented as connectedbetween two subsurface control pods and a utilization function. Controlpod 12 is connected via line 13 to one input of valve while pod isconnected via line 14 to another input of valve 10. Pods 12 and 15 aretypical pods which are manufactured by Offshore Systems Inc., Houston,Texas. These pods are connected to subsurface devices such as oil wellsor the like. In particular, the pods may be connected to blowoutpreventer stacks to effect control thereof. More particularly, in thesystem described, pods 12 and 15 are identical and provide redundantcontrol. This redundancy permits the subsea apparatus to be selectivelycontrolled by pod 12 or 15 so that a malfunction in one pod will notcause the production operation to be shut down. That is, if amalfunction occurs in one pod, it may be disconnected from the subseaunit, taken to the surface and repaired while the second pod isconnected to in control of the subsea unit.

Referring now to FIGS. 1, 2 and 3, it is seen that valve 10 includes aplurality of parts. Body 16 is the centrally located member which has asquare or rectangular configuration and an axial bore of circular crosssection therethrough. This bore is designated by the surface 168.Inaddition, a second bore having a circular configuration and whichintersects the first bore is provided in body 16. The second bore passesthrough the bottom surface of body 16 through the first bore and intothe outer wall of the top of the center body 16. The second bore isrepresented by surface 16A in FIGS. 2 and 3. Bores 16A and 168 may bemolded into body 16 or produced by a suitable drill or boring technique.The second bore represented by lined surface 16A does not passcompletely through the upper surface of body 16. This partial boreprovides a seating location for balance plate 20. Balance plate 20 is,in this embodiment, circular in cross section and has the surface 47thereof lapped and polished. This surface is relatively critical as asealing surface. Consequently, a fine finish is applied thereto.

The aperture or hole which is produced in the lower surface of body 16by passing the second bore therethrough is provided to receive sealplate 21. Seal plate 21 includes a lapped and polished surface 46 which,is also a relatively critical sealing surface and has the same finish assurface 47 of balance plate 20. In addition, seal plate 21 includesshoulders which extend over the outer surface of body 16 to retain sealplate 21 in the position shown. An annular groove is provided on theouter surface of seal plate 21 and O-ring 22 is inserted therein. In thepreferred embodiment, the annular groove and O-ring are locatedimmediately adjacent the shoulder portion of seal plate 21. Obviously,seal plate 21 has a substantially circular cross sectional configurationto meet with the circular configuration of the aperture produced by theboring operation. An axial bore 45 is provided in seal plate 21. 7

Outlet flange 40 has a substantially rectangular configuration and isjoined to body 16 by means of bolts 41. Suitable lock washers or thelike may be utilized. Outlet flange 40 has a recessed portion whichrecess has the configuration appropriate to receive the outer surface ofseal plate 21. Thus, the recess in outlet flange 40 is substantiallycircular in cross section and as deep as the thickness of the shoulderson seal plate 21. Port 44 which extends through outlet flange 40communicates with bore 45 which extends completely through seal plate21. The exterior end of port 44 may be tapped to provide a threadedconnection with line 43 which is connected to function 42. In general,port 44 is usually of a larger diameter than port 45 to reduce alignmentproblems. An annular groove is formed on the inner surface outlet flange40 concentric with and surrounding port 44. An O-ring 24 is located inthe annular groove and effects a seal between seal plate 21 and outletflange 40 concentric to ports 44 and 45.

Piston 25 includes a centrally located and enlarged portion 48 and apair of arms which extend from opposite sides of the center portion.Bores 51 and 26 are provided in the elongated or enlarged centralportion of the piston. These bores extend completely through the centralportion 48. Bores 51 and 26 are off center" relative to the piston aswill be noted hereinafter. In addition, bores 49 and 50 are provided inthe arms of the piston. Each of bores 49 and 50 extend axially along thearms from the end surfaces 75 and 76 and communicate with an associatedone of the seal bores. For example, bore 49 communicates with seal bore26 while bore 50 communicates with seal bore 51. Thus, as will be seenhereinafter, fluid may flow through the bore 49 or 50 into therespective seal bore 26 or 51 without intercommunicating or interactingwith the fluid in the other bore. The arms of the piston aresubstantially cylindrical and have a substantially circular crosssection. The enlarged portion 48 has a substantially cubicalconfiguration with rounded corners to better cooperate with the centralbore in body 16. Alternatively, enlarged portion 48 may be viewed as alarger cylindrical member having flattened surfaces. The flattenedsurfaces of enlarged portion 48 are adapted to move adjacent to but notto abut against the lapped and polished surfaces 47 and 46 of balanceplate 20 and seal plate 21 respectively. Since enlarged portion 48 doesnot touch the polished surfaces, the surface of the piston need not bepolished.

Coil springs 52 and 27 are inserted in bores 51 and 26 respectively. Aseparate seal 29 is inserted in each end of each bore 26 and 51. Theseal 29 has a lapped and polished surface on the exterior portionthereof which lapped and polished surface abuts upon the lapped andpolished surfaces 46 and 47 of balance plate 20 and seal plate 21,respectively. Seal 29 (see FIG. 4 for detail) includes an O-ring 28which is inserted in an annular, peripheral groove, to prevent leakagearound the seal. Seals 29 are urged outwardly, relative to the bores, bycoil springs 52 and 27 whereby the seals are maintained in closeabutment to the polished surfaces of balance plate 20 and seal plate 21.Thus, fluid which is supplied to either of the seal bores cannot leakaround seals 29 and is confined to the respective bores unless alignedwith the outlet port. In addition, since bores 26 and 51 extendcompletely through enlarged portion 4i;v of piston 25, a balancedcondition is achieved relative to the piston inasmuch as equal pressuresare applied on the balance plate and the seal plate.

At either endof the valve is an end cap 17 or 18. End caps 17 and 18 areidentical in configuration. The end cap includes a substantially square,exterior configuration of its base member which is compatible with andcontiguous with the external configuration of body 16. The interior endof end cap 17 or 18 is a reduced portion which may typically have acylindrical configuration to be closely fitted with the inner surface ofbore 16B in body 16. The interior portion of end caps 17 and 18 are ofsufficient length to permit a satisfactory engagement of the end capwith body 16. An annular groove is provided around the periphery of thereduced dimensioned inner end immediately adjacent the larger outer end.O-rings 31 and 36 are inserted in the annular grooves of end caps 17 and18, respectively.

Each of end caps 17 and 18 have an axial bore therethrough. At the outerend or surface, the bore has a typical dimension for example one-quarterinch or the like and may be threaded to receive an input line such aslines 13 or 14. At the interior end of the end cap, the bore is of asuitable dimension to receive the arms of piston 25. Annular grooves areprovided on the inner surface of the bore at the inner end of the endcaps and O-rings 30 and 37 are inserted in the annular grooves toprovide a seal with the outer surface of the arms of piston 25. Thecenter portion of the bore in the end cap is an underreemed or enlargedportion 33 or 35. While it is not essential that these portions beenlarged cavities, the advantage of providing for lubrication to thearms of piston 25 and avoiding excessive binding on the arms of thepiston is provided. End caps 17 and 18 are connected to body 16 bysuitable bolts 19. Lock washers may be utilized if desirable.

ln operation, the valve is connected between two control units or pods12 and 15. Each of these pods is connected to an inlet port 34 or 32 vialines 13 or 14, respectively. A function or utilization device 42 isconnected via line 43 to output port 44.

In the position shown, it is assumed that pod is operable and exertingcontrol over function 42. Thus, hydraulic fluid or the like exertspressure from pod 15 via line 14 to the valve. For example, fluidpressure enters port 32, cavity 33, port 50 and seal port 51. The fluid,being incompressible, exerts pressure against the outer surface 75 ofone arm of piston 25. In addition, the fluid exerts pressure on theinner wall of seal bore 51 thereby forcing piston 25 to the positionshown in FIG. 1. Of course, if pod 15 is operable, pod 12 is understoodto be inoperative whereby substantially no pressure is applied to theother end of piston 25.

With the piston in the position shown in FIG. 1, hydraulic fluid flowsfrom pod 15 through line 14, port 32, cavity 33, port 50, seal port 51,to outlet ports 45 and 44, and is supplied via line 43 to function 42.In this manner, pod 15 effects control over function 42.

If now it is assumed that pod 15 becomes inoperative, as for example aleak or malfunction occurs therein, pod 15 will be rendered inoperativeby the control unit at the surface location. Simultaneously, pod 12 willbe activated to assume control. When pod 12 is activated, fluid willflow through line 13 to port 34. Fluid will abut against and applypressure to surface 76 of piston 25. Concurrently, fluid will passthrough port 49 into seal port 26 and exert pressure on the innersurface thereof. Since port 26 is sealed at either end due to theabutment of seals 29 against sealing surfaces 47 and 46, the fluidcannot escape and continued pressure is supplied against the innersurface of seal bore 26. Since seal bore 26 experiences a relativelylarge pressure against the inner surface thereof and no pressure isapplied to seal bore 51, piston 25 is forced to move, in this caseleftwardly, until bore 51 is totally removed from communication withseal plate bore 45 and bore 26 is in communication therewith. When bore26 is in communication with seal plate bore 45, the pressure is releasedthrough bore 45 and outlet port 46 to function 42 thereby to effect acontrol operation.

It should be noted, that bores 26 and 51 are arranged in the enlargedportion 48 of piston 25 so that seal plate bore 45 communicates with oneand only one of the seal bores at any time. That is, the distancebetween the seal bores is greater than the diameter of seal plate bore45. Therefore, bore 45 cannot communicate with both seal boressimultaneously. Moreover, seals 29 prevent spurious interaction due toleakage. This eliminates any possible ambiguity which could occur in thevalve operation if both seal bores could simultaneously communicate withseal plate bore 45.

in reversing the operation, if pod 12 is rendered inoperative for somereason, and pod 15 is activated, piston 25 will be forced to theposition shown in FIG. 1 wherein pod 15 will communicate with function42 and effect control thereof.

Referring now to FIG. 4, there is a detailed cross-sectional showing ofthe sealing arrangement relative to the seal bore. In particular, sealbore 51 is shown. Seal 29 is represented at the bottom portion of theseal bore. Coil spring 52 is shown exerting pressure on seal 29 toassure contact between the outer surface of seal 29 and the lapped andpolished surface 46 of seal plate 21. O-ring 28 is provided in anannular groove in seal 29 to prevent leakage around seal 29. The centralbore 101 of seal 29 is depicted as having a slightly larger diameterthan the diameter of outlet port 45. The clearance between enlargedsection 48 of piston 25 and the polished surface 46 of seal plate 21 isexaggerated to show same more clearly. However, due to spring 52, seal29 is forced into abutment with the surface 46 to prevent leakage aroundenlarged portion 48 of piston 25.

Thus, there has been shown and described a shuttle valve which requirespositive pressure to produce positive displacement of the shuttle. Thepressure may be provided by a very small amount of fluid applied at arelatively slow rate. The flow rate of the fluid is not essential toeffecting positive displacement. The flow rate affects only the responsetime of the valve. That is, a relatively slow fluid flow rate willrequire a longer time period to exert sufficient pressure to move thepiston in the shuttle valve. However, as in the case of known shuttlevalves, the low fluid flow rate will not cause the piston to move to anambiguous position and then leak around the piston to render the entiresystem ineffective. This valve is a substantially closed loop or systemvalve wherein each of separate control systems are totally isolated onefrom the other and interdependence or interrelationship therebetweencannot be seriously effected.

Having thus described the invention, what is claimed is:

l. A shuttle valve adapted to permit the control of afluidpressure-operated utilization device from either one of twoseparate fluid-pressure-supplying control units comprising:

a. a body member having a longitudinally extending axial bore therein,and a transversely extending second bore passing through the bottomsurface of the body member, intersecting said axial bore, and extendinginto the outer wall at the top of said body member providing a partialbore therein;

b. a balance plate positioned in said partial bore and having a polishedsurface on the side thereof facing the interior of the body member;

c. a seal plate positioned in the portion of said second bore extendingthrough the bottom portion of said body member, said seal plate havingan axial bore extending therethrough from the bottom surface of saidseal plate and communicating with the axial bore in said body member,said seal plate having a polished surface in the side thereof facing theinterior of the body member;

d. piston 'means positioned in said axial bore in the body member andadapted for movement therein between a first end position in which thepiston means is positioned in a first furthermost position at one end ofsaid body member and a second end position in which the piston means ispositioned in a second furthermost position at the opposite end of thebody member, said piston means having a central portion having first andsecond bores extending transversely completely therethrough from the topto the bottom thereof, said piston means also having first and secondarm portions extending longitudinally from said central portion, saidfirst arm portion having an axial bore extending therethrough from theend surface thereof and communicating with said first transverselyextending bore in the central portion, said second arm portion having anaxial bore extending therethrough from the end surface thereof andcommunicating with said second transversely extending bore in thecentral portion, said piston means being positioned so that, in saidfirst end position, said first bore in the central portion thereof is incommunication with the bore in said seal plate, and, in said second endposition, said second bore in the central portion thereof is incommunication with said bore in the seal plate;

e. seal means positioned at each end of each of said bores extendingthrough the central portion of said piston means. each of said sealshaving a polished surface on the exterior portion thereof that abutsupon the polished surfaces of said balance plate and said seal plate;

f. spring means to maintain said seal means in contact with the polishedsurfaces of said balance plate and said seal plate;

g. first input conduit means for providing fluid communication between afirst control unit and the axial bore in said first arm portion of thepiston means;

h. second input conduit means for providing fluid communication betweena second control unit and the axial bore in said second arm portion ofthe piston means;

i. output conduit means providing fluid communication between the axialbore in said seal plate and the fluidpressure-operated utilizationdevice to be controlled,

whereby when said first control units is operative, fluid flows throughsaid first input conduit means to the axial bore in the first armportion of the piston means, the fluid pressure therein beingtransmitted to said first bore in the central portion of said pistonmeans, the polished surfaces of the balance plate, the seal plate andsaid sealing means permitting the shuttle valve to slide to its firstend position in which said first bore communicates with the bore in theseal plate, thereby establishing fluid communication to the utilizationdevice, whereas when said first control unit is inoperative and saidsecond control unit is operative, the piston means is caused to slide toits second end position so as to establish fluid communication from thesecond control unit through the axial bore in said second arm portion,said second bore in the central portion and said bore in the sealingplate to the utilization device,

the positive fluid pressure required to cause said piston means to slidebetween the first and second end positions being operative at relativelylow flow rates, the flow rate only affecting the response time of thevalve in switching from said first to said second end positions.

2. The shuttle valve of claim 1 and including a first end cap secured toone end of said body member, said first end cap having an inlet portproviding fluid communication between said first conduit means and theaxial bore in said first arm portion of said piston means, said firstarm portion extending into a cavity at the inner end of said end cap andincluding a second end cap secured to the opposite end of said bodymember, said second end cap having an inlet port providing fluidcommunication between said second conduit means and the axial bore insaid second arm portion of the piston means, said second arm portionextending into a cavity at the inner end of said second end cap, andfurther including sealing means between said body member and said firstand second end caps, and between said first and second end caps and saidfirst and second arm portions of the piston means.

3. The shuttle valve of claim 2 in which said central portion of thepiston means is enlarged, the end portions of said central portioncontacting the inner surfaces of said end caps at said first and secondend positions of said piston means.

4. The shuttle valve of claim 3 and including an outlet flange membersecured to the bottom portion of said body member, said outlet flangemember covering said seal plate, said flange member having a boreextending therethrough to provide fluid communication between the borein said seal plate and the output conduit means.

5. The shuttle valve of claim 4 and including sealing means between saidoutlet flange and said seal plate to prevent the flow of fluid from thebore in said seal plate outside said shuttle valve other than throughthe bore in said flange member and said outlet conduit means to theutilization device.

1. A shuttle valve adapted to permit the control of afluidpressure-operated utilization device from either one of twoseparate fluid-pressure-supplying control units comprising: a. a bodymember having a longitudinally extending axial bore therein, and atransversely extending second bore passing through the bottom surface ofthe body member, intersecting said axial bore, and extending into theouter wall at the top of said body member providing a partial boretherein; b. a balance plate positioned in said partial bore and having apolished surface on the side thereof facing the interior of the bodymember; c. a seal plate positioned in the portion of said second boreextending through the bottom portion of said body member, said sealplate having an axial bore extending therethrough from the bottomsurface of said seal plate and communicating with the axial bore in saidbody member, said seal plate having a polished surface in the sidethereof facing the interior of the body member; d. piston meanspositioned in said axial bore in the body member and adapted formovement therein between a first end position in which the piston meansis positioned in a first furthermost position at one end of said bodymember and a second end position in which the piston means is positionedin a second furthermost position at the opposite end of the body member,said piston means having a central portion having first and second boresextending transversely completely therethrough from the top to thebottom thereof, said piston means also having first and second armportions extending longitudinally from said central portion, said firstarm portion having an axial bore extending therethrough from the endsurface thereof and communicating with said first transversely extendingbore in the central portion, said second arm portion having an axialbore extending therethrough from the end surface thereof andcommunicating with said second transversely extending bore in thecentral portion, said piston means being positioned so that, in saidfirst end position, said first bore in the central portion thereof is incommunication with the bore in said seal plate, and, in said second endposition, said second bore in the central portion thereof is incommunication with said bore in the seal plate; e. seal means positionedat each end of each of said bores extending through the central portionof said piston means, each of said seals having a polished surface onthe exterior portion thereof that abuts upon the polished surfaces ofsaid balance plate aNd said seal plate; f. spring means to maintain saidseal means in contact with the polished surfaces of said balance plateand said seal plate; g. first input conduit means for providing fluidcommunication between a first control unit and the axial bore in saidfirst arm portion of the piston means; h. second input conduit means forproviding fluid communication between a second control unit and theaxial bore in said second arm portion of the piston means; i. outputconduit means providing fluid communication between the axial bore insaid seal plate and the fluid-pressureoperated utilization device to becontrolled, whereby when said first control units is operative, fluidflows through said first input conduit means to the axial bore in thefirst arm portion of the piston means, the fluid pressure therein beingtransmitted to said first bore in the central portion of said pistonmeans, the polished surfaces of the balance plate, the seal plate andsaid sealing means permitting the shuttle valve to slide to its firstend position in which said first bore communicates with the bore in theseal plate, thereby establishing fluid communication to the utilizationdevice, whereas when said first control unit is inoperative and saidsecond control unit is operative, the piston means is caused to slide toits second end position so as to establish fluid communication from thesecond control unit through the axial bore in said second arm portion,said second bore in the central portion and said bore in the sealingplate to the utilization device, the positive fluid pressure required tocause said piston means to slide between the first and second endpositions being operative at relatively low flow rates, the flow rateonly affecting the response time of the valve in switching from saidfirst to said second end positions.
 2. The shuttle valve of claim 1 andincluding a first end cap secured to one end of said body member, saidfirst end cap having an inlet port providing fluid communication betweensaid first conduit means and the axial bore in said first arm portion ofsaid piston means, said first arm portion extending into a cavity at theinner end of said end cap and including a second end cap secured to theopposite end of said body member, said second end cap having an inletport providing fluid communication between said second conduit means andthe axial bore in said second arm portion of the piston means, saidsecond arm portion extending into a cavity at the inner end of saidsecond end cap, and further including sealing means between said bodymember and said first and second end caps, and between said first andsecond end caps and said first and second arm portions of the pistonmeans.
 3. The shuttle valve of claim 2 in which said central portion ofthe piston means is enlarged, the end portions of said central portioncontacting the inner surfaces of said end caps at said first and secondend positions of said piston means.
 4. The shuttle valve of claim 3 andincluding an outlet flange member secured to the bottom portion of saidbody member, said outlet flange member covering said seal plate, saidflange member having a bore extending therethrough to provide fluidcommunication between the bore in said seal plate and the output conduitmeans.
 5. The shuttle valve of claim 4 and including sealing meansbetween said outlet flange and said seal plate to prevent the flow offluid from the bore in said seal plate outside said shuttle valve otherthan through the bore in said flange member and said outlet conduitmeans to the utilization device.